Method and apparatus for communicating ism prone frequency information to a base station

ABSTRACT

A method and an apparatus for handling in-device coexistence interference in a user equipment are provided. The method includes receiving a list of non-serving Long Term Evolution (LTE) frequencies from a base station, configuring the non-serving LTE frequencies so as to perform a measurement on the configured non-serving LTE frequencies, and detecting a likelihood of in-device coexistence interference between at least one of the non-serving LTE frequencies and an Industrial, Scientific and Medical (ISM) frequency when an ISM activity is ongoing on the ISM frequency.

PRIORITY

This application is a National Stage application under 35 U.S.C. §371 ofan International application filed on Jan. 6, 2012 and assignedapplication No. PCT/KR2012/000175, and claims the benefit under 35U.S.C. §365(b) of an Indian patent application filed on Jan. 7, 2011 inthe Indian Intellectual Property Office and assigned Serial No.62/CHE/2011, the entire disclosure of each of which is herebyincorporated by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a wireless communication system. Moreparticularly, the present invention relates to a method of handlingin-device coexistence in a user equipment.

2. Description of the Related Art

Coexistence of Long Term Evolution (LTE) with the Industrial, Scientificand Medical (ISM) (Bluetooth®, Wireless Fidelity (Wi-Fi®), and the like)band technologies and Global Navigation Satellite Systems (GNSS) isnecessary to be provided as these are becoming very common combinationsin User Equipments (UEs), such as cell phones. Each of thesetechnologies is developed by a different group to serve a specificpurpose. Characteristics of each of these technologies are different.They operate in different frequencies, have different access mechanism,have different frame structure, and peak transmit power.

When all these technologies operate simultaneously in an adjacent band,(a small separation e.g., <20 MHz) usually 50 decibels (dB) of isolationis required. However, a small form factor of the UE provides only 10-30dB isolation. As a result, the transmitter of one radio severely affectsthe receiver of another radio. For example, a small form factor of theUE may pose great challenge of in-device coexistence interference fromtransmission of ISM technology to the receiver of cellular technologies,such as LTE or Worldwide Interoperability for Microwave Access (WiMax®).Similarly, the transmitter of cellular technology may cause severein-device coexistence interference to the ISM receiver. The main causeof in-device co-existence issues may be because of receiver blocking dueto a limited dynamic range of power amplifier, an Analog to Digitalconverter and out of band emission due to imperfect filtering.

LTE Coexistence with Bluetooth®

FIG. 1A is a schematic diagram illustrating a separation between LTE andBluetooth® channels according to the related art.

Referring to FIG. 1A, an LTE band 7 UL and Bluetooth® band are separatedby 20 MHz frequency band. The band 7 is Frequency Division Duplexing(FDD) band and hence the LTE receiver is not affected by the Bluetooth®transmitter whereas the LTE transmitter can affect the Bluetooth®receiver. In addition, there is very negligible separation of 2 MHzbetween LTE band 40 (i.e., a Time Division Duplexing (TDD) band) and theBluetooth® frequency band. Therefore, it is not possible to discontinueusing higher portion of LTE band 40 in a case of coexistence.

LTE Co-Existence with Wi-Fi®

FIG. 1B is a schematic diagram illustrating a separation between LTE andWi-Fi® channels according to the related art.

Referring to FIG. 1B, there are 14 channels demarcated in an ISM bandfor a Wi-Fi® operation. Each channel is separated by 5 MHz with anexception of channel number 14, which is separated by 12 MHz. Channel 1starts with 2401 MHz and hence there is almost no separation between LTEband 40 and Wi-Fi®. Channel 14 of Wi-Fi® ends at 2495 MHz, sotheoretically only 5 MHz separation is available between the LTE band 7and the Wi-Fi®. Different countries have different policies for a numberof allowed channels of the Wi-Fi®. Currently, many countries allow onlychannel 1 to 13 whereas usage of channel number 14 is only allowed foran Institute of Electrical and Electronics Engineers (IEEE) 802.11bbased communication. This suggests that even though in theory only 5 MHzseparation is available between the Wi-Fi® and the LTE band 7, at least17 MHz is available in practice.

Currently known solutions for handling in-device co-existence includes aTime Division Multiplexing (TDM) based solution, a Frequency DivisionMultiplexing (FDM) based solution or a combination of both. In an FDMbased solution, a UE is configured to report a presence of in-devicecoexistence interference between a serving LTE frequency of the LTE bandand an ISM frequency of the ISM band to a base station. Accordingly, thebase station decides to handover the UE to a different frequency notaffected by an ISM activity or not affecting the ISM activity.Additionally, when the ISM activity has completed, the UE informs thesame to the base station.

Therefore, a need exists for a method of handling in-device coexistencein a UE.

The above information is presented as background information only toassist with an understanding of the present disclosure. No determinationhas been made, and no assertion is made, as to whether any of the abovemight be applicable as prior art with regard to the present invention.

SUMMARY OF THE INVENTION

Aspects of the present invention are to address at least theabove-mentioned problems and/or disadvantages and to provide at leastthe advantages described below. Accordingly, an aspect of the presentinvention is to provide a method of handling in-device coexistence in aUser Equipment (UE).

FIG. 2 is a schematic diagram illustrating a ping pong scenario duringhandover of a User Equipment (UE) between an LTE frequency not affectedby an ISM frequency and another LTE frequency affected by the ISMfrequency according to an embodiment of the present invention.

Typically, a base station configures a UE with one or more non-servingLong Term Evolution (LTE) frequencies for performing measurements. Themeasurements are performed on these frequencies as the base station canhandover the UE from the serving frequency to any of one or morenon-serving LTE frequencies based on the measurements. The target LTEfrequency selected for handover may be affected by an Industrial,Scientific and Medical (ISM) activity. However, when the base stationperforms the handover to the target LTE frequency, the base station isnot aware that the target LTE frequency is affected by the ISM activityor will affect the ISM activity. As a consequence, the base stationperforms handover of the UE to the target LTE frequency. Thus, the UEmay request the base station to move it away from the affected targetLTE frequency. This may lead to a ping-pong effect between an LTEfrequency affected by the ISM activity and an LTE frequency not affectedby the ISM activity similar to the scenario illustrated in FIG. 2.

In accordance with an aspect of the present invention, a method isprovided. The method includes detecting a likelihood of in-devicecoexistence interference between at least one of non-serving LTEfrequencies and an ISM frequency when an ISM activity is ongoing on theISM frequency, and reporting the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency to a base station.

In accordance with another aspect of the present invention, an apparatusis provided. The apparatus includes a processor, and a memory coupled tothe processor, wherein the memory includes an interference handlerconfigured to detect a likelihood of in-device coexistence interferencebetween at least one of non-serving LTE frequencies and an ISM frequencywhen an ISM activity is ongoing on the ISM frequency, and configured toreport the likelihood of in-device coexistence interference between theat least one of the non-serving LTE frequencies and the ISM frequency toa base station.

Other aspects, advantages, and salient features of the invention willbecome apparent to those skilled in the art from the following detaileddescription, which, taken in conjunction with the annexed drawings,discloses various embodiments of the invention.

BRIEF DESCRIPTION OF DRAWINGS

The above and other aspects, features, and advantages of certainembodiments of the present invention will be more apparent from thefollowing description taken in conjunction with the accompanyingdrawings, in which:

FIG. 1A is a schematic diagram illustrating a separation between LongTerm Evolution (LTE) and Bluetooth® channels according to the relatedart.

FIG. 1B is a schematic diagram illustrating a separation between LTE andWireless Fidelity (Wi-Fi®) channels according to the related art.

FIG. 2 is a schematic diagram illustrating a ping pong scenario duringhandover of a user equipment between an LTE frequency not affected by anIndustrial, Scientific and Medical (ISM) frequency and another LTEfrequency affected by the ISM frequency according to an embodiment ofthe present invention.

FIG. 3 is a block diagram illustrating a wireless communication systemcapable of handling in-device co-existence interference between one ormore non-serving LTE frequencies and an ISM frequency configured for auser equipment according to an embodiment of the present invention.

FIG. 4 is a flowchart illustrating a method of handling in-deviceco-existence interference between one or more non-serving LTEfrequencies and an ISM frequency configured for a user equipmentaccording to an embodiment of the present invention.

FIG. 5 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 6 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 7 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 8 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 9 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 10 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

FIG. 11 illustrates a block diagram of a coordinator according to anembodiment of the present invention.

The drawings described herein are for illustration purposes only and arenot intended to limit the scope of the present disclosure in any way.

Throughout the drawings, like reference numerals will be understood torefer to like parts, components, and structures.

DETAILED DESCRIPTION OF EMBODIMENTS

The following description with reference to the accompanying drawings isprovided to assist in a comprehensive understanding of exemplaryembodiments of the invention as defined by the claims and theirequivalents. It includes various specific details to assist in thatunderstanding but these are to be regarded as merely exemplary.Accordingly, those of ordinary skill in the art will recognize thatvarious changes and modifications of the embodiments described hereincan be made without departing from the scope and spirit of theinvention. In addition, descriptions of well-known functions andconstructions may be omitted for clarity and conciseness.

The terms and words used in the following description and claims are notlimited to the bibliographical meanings, but, are merely used by theinventor to enable a clear and consistent understanding of theinvention. Accordingly, it should be apparent to those skilled in theart that the following description of exemplary embodiments of thepresent invention is provided for illustration purpose only and not forthe purpose of limiting the invention as defined by the appended claimsand their equivalents.

It is to be understood that the singular forms “a,” “an,” and “the”include plural referents unless the context clearly dictates otherwise.Thus, for example, reference to “a component surface” includes referenceto one or more of such surfaces.

By the term “substantially” it is meant that the recited characteristic,parameter, or value need not be achieved exactly, but that deviations orvariations, including for example, tolerances, measurement error,measurement accuracy limitations and other factors known to those ofskill in the art, may occur in amounts that do not preclude the effectthe characteristic was intended to provide.

FIG. 3 is a block diagram illustrating a wireless communication systemcapable of handling in-device co-existence interference between one ormore non-serving Long Term Evolution (LTE) frequencies and anIndustrial, Scientific and Medical (ISM) frequency configured for a userequipment according to an embodiment of the present invention.

Referring to FIG. 3, a wireless communication system 300 includes a UserEquipment (UE) 301 and a base station (e.g., an evolved Node B (eNB))310 connected to the UE 301 via a wireless network (e.g., an LTEnetwork) 312. The UE 301 includes an LTE module 302, a coordinator 304and an ISM module 304.

Consider that the UE 301 is operating in the connected mode and performsuplink and downlink data transmission with the base station 310 over aserving LTE frequency. In addition, consider that, during the operationof the UE 301 in the connected mode, the base station 310 configuresnon-serving LTE frequencies for the UE 301 to perform a measurement onthe non-serving LTE frequencies. Thereafter, the base station 310 sendsa list of the non-serving LTE frequencies to the UE 301. Accordingly,the coordinator 304 configures the non-serving LTE frequencies forperforming measurements in corresponding measurement gaps.

During the operation in a connected mode, consider that the coordinator304 detects that there is a likelihood of in-device co-existenceinterference between one or more configured non-serving LTE frequenciesand an ISM frequency on which an ISM activity is performed by the ISMmodule 306. Thus, the coordinator 304 reports that the ISM activity isongoing and there is a likelihood of in-device coexistence interferencebetween the one or more non-serving LTE frequencies and the ISMfrequency to the base station 310. Therefore, the base station 310avoids performing handover of the UE 301 to the one or more serving LTEfrequencies affected by the ISM frequency. In a case of handover, thebase station 310 may communicate the likelihood of in-device coexistenceinterference to another base station with which the handover of the userequipment 301 is performed.

The ISM module 306 may be turned off upon completion of the ongoing ISMactivity. When the ISM module 306 is turned off, the coordinator 304detects that the ISM module 306 is turned off and hence the coordinator304 reports to the base station 310 that the ISM activity has completedand the ISM module 306 is turned off. Thus, the coordinator 304 canreconfigure the one or more non-serving LTE frequencies for performingmeasurements. In addition, the base station 310 may consider any of theone or more non-serving LTE frequencies for handover from the servingfrequency from the user equipment 301.

Alternatively, in one embodiment of the present invention, the basestation 310 sets a timer value for which the one or more non-serving LTEfrequencies are blocked for performing a measurement. In addition, thebase station 310 sends the timer value to the user equipment 301.Further, the base station 310 sends an updated list of the non-servingLTE frequencies to the user equipment 301 upon expiry of the timervalue, where the updated list includes the at least one of thenon-serving LTE frequencies previously affected by the ISM activity.Accordingly, the user equipment 301 configures the non-serving LTEfrequencies in the updated list for performing a measurement.

In another embodiment of the present invention, the user equipment 301sets a timer value during which the at least one of the non-serving LTEfrequencies is to be blocked for performing a measurement. The UE 301communicates the timer value to the base station 310 while reporting thelikelihood of in-device coexistence interference between the at leastone of the non-serving LTE frequencies and the ISM frequency to the basestation. The base station 310 sends an updated list of the non-servingLTE frequencies upon expiry of the timer value, where the updated listof the non-serving frequencies includes the at least one of thenon-serving LTE frequencies. Accordingly, the user equipment 301configures the non-serving LTE frequencies in the updated list forperforming a measurement.

In yet another embodiment of the present invention, the UE 301 sets atimer value during which the at least one of non-serving LTE frequenciesis to be blocked for performing a measurement. Further, the UE 301 addsthe removed at least one of the non-serving LTE frequencies in the listof the non-serving LTE frequencies for performing measurements uponexpiry of the timer value.

In the above embodiments of the present invention, the expiry of thetimer value indicates that the ISM activity has completed. In otherwords, the expiry of timer value indicates that the one or morenon-serving LTE frequencies are no more likely to be affected by the ISMactivity as the ISM module 306 is turned off. Thus, the UE 301 canperform measurements on the previously affected non-serving LTEfrequencies and the base station 310 may consider any of the one or morenon-serving LTE frequencies for handover from the serving frequency fromthe user equipment 301 upon expiry of the timer value (i.e., uponcompletion of the ISM activity).

FIG. 4 is a flowchart illustrating a method of handling in-deviceco-existence interference between one or more non-serving LTEfrequencies and an ISM frequency configured for a user equipmentaccording to an embodiment of the present invention.

Referring to FIG. 4, at operation 402, a list of non-serving LTEfrequencies to be configured for performing measurements is receivedfrom the base station 310. At operation 404, the non-serving LTEfrequencies in the received list are configured by the user equipment301.

When the LTE module 302 is performing LTE activity on a serving LTEfrequency, the controller 304 determines that the ISM module 306 isswitched on for performing ISM activity on an ISM frequency. In such acase, at operation 406, the UE detects a likelihood of in-deviceco-existence interference between one or more of the non-serving LTEfrequencies and the ISM frequency. Accordingly, at operation 408, thelikelihood of in-device co-existence interference between one or morenon-serving LTE frequencies and the ISM frequency is reported to thebase station.

At operation 410, a response message with an instruction to remove theone or more non-serving LTE frequencies from the list of configurednon-serving LTE frequencies is received from the base station 310. Atoperation 412, the one or more non-serving LTE frequencies andcorresponding measurement gaps are removed from the list of configurednon-serving LTE frequencies by the user equipment 301. In an alternateembodiment of the present invention, the one or more non-serving LTEfrequencies and corresponding measurement gaps are automatically removedfrom the list by the user equipment 301 upon detecting the likelihood ofin-device co-existence interference. In other words, the one or morenon-serving LTE frequencies are de-configured for performingmeasurements till the ISM activity is ongoing on the ISM frequency.

In one embodiment of the present invention, the user equipment 301avoids performing measurements on the one or more non-serving LTEfrequencies affected by the ongoing ISM activity in the measurementgaps. In another embodiment of the present invention, the base station310 avoids performing handover from the serving frequency to any of theone or more non-serving LTE frequencies by the ongoing ISM activity.Upon completion of the ISM activity, the user equipment 301 informs thebase station 310 that the ISM activity is complete and there is nolikelihood of in-device co-existence interference between the one ormore non-serving LTE frequencies and the ISM frequency. Thus, the userequipment 301 can reconfigure the one or more non-serving LTEfrequencies for performing measurements. In addition, the base station310 may consider any of the one or more non-serving LTE frequencies forhandover from the serving frequency based on the measurement report fromthe user equipment 301.

FIG. 5 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 5, at operation 502, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation504, the base station 310 sends a list of the non-serving LTEfrequencies to the user equipment 301. At operation 506, the userequipment 301 configures the non-serving LTE frequencies for performingmeasurements in corresponding measurement gaps.

At operation 508, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between one or moreconfigured non-serving LTE frequencies and an ISM frequency on which anISM activity is performed by the ISM module 306. At operation 510, theuser equipment 301 reports that the ISM activity is ongoing and there isa likelihood of in-device coexistence interference between the one ormore non-serving LTE frequencies and the ISM frequency to the basestation 310 in a measurement report or any other new message. Forexample, the UE 301 sends a measurement report indicating that there isa likelihood of in-device co-existence interference upon availability ofmeasurement results or may send the indication through a new messageupon detection of the likelihood of in-device co-existence interference.Thus, the base station 310 avoids performing handover of the userequipment 301 to the one or more serving LTE frequencies affected by theISM frequency.

The base station 310 may communicate the likelihood of in-devicecoexistence interference to another base station with which the handoverof the user equipment 301 is performed. Further, if there are anymeasurement gaps for performing the measurement, the UE 301 and the basestation 310 may continue or discontinue with the measurement gaps bycommunicating synchronously with the base station 310. For example, theUE 301 may send such information as part of the measurement report ifthe non-serving LTE frequencies affected by the ISM activity areobserved to be stronger.

The ISM module 306 is turned off when the ongoing ISM activity iscomplete. When the ISM module 306 is turned off, at operation 512, theuser equipment 301 detects that the ISM module 306 is turned off. Atoperation 514, the user equipment 301 reports to the base station 310that the ISM activity is complete and the ISM module 306 is turned off.Thus, the user equipment 301 can reconfigure the one or more non-servingLTE frequencies for performing measurements. In addition, the basestation 310 may consider any of the one or more non-serving LTEfrequencies for handover from the serving frequency based on themeasurement report from the user equipment 301.

FIG. 6 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 6, at operation 602, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation604, the base station 310 sends a Radio Resource Connection (RRC)reconfiguration message with a list of the non-serving LTE frequenciesto the user equipment 301. At operation 606, the user equipment 301configures the non-serving LTE frequencies listed in the RRCreconfiguration message for performing measurements in correspondingmeasurement gaps.

At operation 608, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between one or moreconfigured non-serving LTE frequencies and an ISM frequency on which anISM activity is performed by the ISM module 306. At operation 610, theuser equipment 301 reports that the ISM activity is ongoing and there isa likelihood of in-device coexistence interference between the one ormore non-serving LTE frequencies and the ISM frequency to the basestation 310 in a measurement report. At operation 612, the base station310 sends a measurement reconfiguration message with an instruction toremove the one or more non-serving LTE frequencies from the list ofnon-serving LTE frequencies configured for performing a measurement. Atoperation 614, the user equipment 301 removes the one or morenon-serving LTE frequencies from the list of configured non-serving LTEfrequencies based on the measurement reconfiguration message.

The ISM module 306 is turned off when the ongoing ISM activity iscomplete. When the ISM module 306 is turned off, at operation 616, theuser equipment 301 detects that the ISM module 306 is turned off. Atoperation 618, the user equipment 301 reports to the base station 310that the ISM activity is complete and the ISM module 306 is turned off.Thus, the user equipment 301 can reconfigure the one or more non-servingLTE frequencies for performing measurements. In addition, the basestation 310 may consider any of the one or more non-serving LTEfrequencies for handover from the serving frequency based on themeasurement report from the user equipment 301.

FIG. 7 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 7, at operation 702, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation704, the base station 310 sends an RRC reconfiguration message with alist of non-serving LTE frequencies to the user equipment 301. Atoperation 706, the user equipment 301 configures the non-serving LTEfrequencies listed in the RRC reconfiguration message for performingmeasurements in corresponding measurement gaps.

At operation 708, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between one or moreconfigured non-serving LTE frequencies and an ISM frequency on which anISM activity is performed by the ISM module 306. At operation 710, theuser equipment 301 sends an RRC reconfiguration complete messageindicating that the ISM activity is ongoing and there is a likelihood ofin-device coexistence interference between the one or more non-servingLTE frequencies and the ISM frequency to the base station 310. In oneimplementation, the RRC reconfiguration message includes a new rejectioncause indicating that one or more non-serving LTE frequencies areaffected by the ISM activity and an information element indicating alist of one or more non-serving LTE frequencies affected by the ISMactivity.

At operation 712, the base station 310 sends a new RRC reconfigurationmessage with an updated list of non-serving LTE frequencies. The updatedlist of non-serving LTE frequencies excludes the one or more non-servingLTE frequencies that are affected by the ongoing ISM activity. Atoperation 714, the user equipment 301 configures the non-serving LTEfrequencies from the updated list of non-serving LTE frequencies forperforming a measurement.

FIG. 8 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 8, at operation 802, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation804, the base station 310 sends an RRC reconfiguration message with alist of non-serving LTE frequencies to the user equipment 301. Atoperation 806, the user equipment 301 configures the non-serving LTEfrequencies listed in the RRC reconfiguration message for performingmeasurements in corresponding measurement gaps.

At operation 808, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between one or moreconfigured non-serving LTE frequencies and an ISM frequency on which anISM activity is performed by the ISM module 306. At operation 810, theuser equipment 301 sends an RRC reconfiguration complete messageindicating that the ISM activity is ongoing and there is a likelihood ofin-device coexistence interference between the one or more non-servingLTE frequencies and the ISM frequency to the base station 310. In oneimplementation, the RRC reconfiguration message includes a new rejectioncause indicating that one or more non-serving LTE frequencies areaffected by the ISM activity and an information element indicating alist of one or more non-serving LTE frequencies affected by the ISMactivity. Although, the RRC reconfiguration is rejected by the UE 301,the connection between the base station 310 and the UE 301 is maintainedand hence no connection re-establishment needs to be performed.

At operation 812, the user equipment 301 removes the one or morenon-serving LTE frequencies and corresponding measurement gaps from thelist of configured non-serving LTE frequencies. It can be noted that theUE 301 may continue to perform measurements on other non-serving LTEfrequencies that are not affected by the ISM activity.

FIG. 9 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 9, at operation 902, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation904, the base station 310 sends an RRC reconfiguration message with ahandover command for performing a handover from the serving LTEfrequency to a configured non-serving LTE frequency.

At operation 906, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between thenon-serving LTE frequency and an ISM frequency on which an ISM activityis performed by the ISM module 306. At operation 908, the user equipment301 rejects the handover command in the RRC reconfiguration message. Atoperation 910, the user equipment 301 sends an RRC reconfigurationcomplete message to the base station 310 indicating that the ISMactivity is ongoing and there is a likelihood of in-device coexistenceinterference between the non-serving LTE frequency and the ISMfrequency. In one implementation, the RRC reconfiguration messageincludes a new rejection cause indicating that the target non-servingLTE frequency is affected by the ISM activity. At operation 912, thebase station 310 sends a new RRC reconfiguration message with a handovercommand for performing handover from the serving LTE frequency toanother non-serving LTE frequency not affected by the ongoing ISMactivity.

When the RRC reconfiguration message is rejected, the RRC connectionneeds to be re-established. However, according to an embodiment of thepresent invention, there is no need for re-establishing the RRCconnection between the UE 301 and the base station 310. In addition,when an RRC reconfiguration message is meant for handover, a source cellmay not be listening to any subsequent message transmitted by the UE301. As the result, a success may be received by a target cell or afailure, which needs a connection re-establishment, may be received by atarget cell.

FIG. 10 is a flow diagram of a method of handling in-device co-existenceinterference between one or more non-serving LTE frequencies and an ISMfrequency configured for a user equipment according to an embodiment ofthe present invention.

Referring to FIG. 10, at operation 1002, the base station 310 configuresnon-serving LTE frequencies for performing a measurement. At operation1004, the base station 310 sends an RRC reconfiguration message with ahandover command for performing a handover from the serving LTEfrequency to a configured non-serving LTE frequency.

At operation 1006, the user equipment 301 detects that there is alikelihood of in-device co-existence interference between thenon-serving LTE frequency and an ISM frequency on which an ISM activityis performed by the ISM module 306. At operation 1008, the userequipment 301 rejects the handover command in the RRC reconfigurationmessage. At operation 1010, the user equipment 301 triggers an RRCre-establishment procedure for re-establishing a radio resourceconnection with the base station 310. At operation 1012, the userequipment 301 sends an RRC re-establishment request message to the basestation 310 indicating that the ISM activity is ongoing and there is alikelihood of in-device coexistence interference between the non-servingLTE frequency and the ISM frequency. In one implementation, the RRCre-establishment request message includes a new rejection causeindicating that the RRC re-establishment procedure is triggered sincethe target non-serving LTE frequency is affected by the ISM activity.

FIG. 11 illustrates a block diagram of a coordinator according to anembodiment of the present invention.

Referring to FIG. 11, a coordinator 304 includes a processor 1102, amemory 1104, a Read Only Memory (ROM) 1106, a bus 1108, and acommunication interface 1110.

The processor 1102, as used herein, means any type of computationalcircuit, such as, but not limited to, a microprocessor, amicrocontroller, a complex instruction set computing microprocessor, areduced instruction set computing microprocessor, a very longinstruction word microprocessor, an explicitly parallel instructioncomputing microprocessor, a graphics processor, a digital signalprocessor, or any other type of processing circuit. The processor 1102may also include embedded controllers, such as generic or programmablelogic devices or arrays, application specific integrated circuits,single-chip computers, smart cards, and the like.

The memory 1104 may be a volatile memory and a non-volatile memory. Thememory 1104 includes an interference handler 1112 for handling in-deviceco-existence interference between non-serving LTE frequencies and an ISMfrequency, according to the embodiments illustrated in FIGS. 3 and 10. Avariety of computer-readable storage media may be stored in and accessedfrom the memory elements. Memory elements may include any suitablememory device(s) for storing data and machine-readable instructions,such as a ROM, a Random Access Memory (RAM), an erasable programmableROM, an electrically erasable programmable ROM, a hard drive, aremovable media drive for handling memory cards, Memory Sticks™, and thelike.

Embodiments of the present subject matter may be implemented inconjunction with modules, including functions, procedures, datastructures, and application programs, for performing tasks, or definingabstract data types or low-level hardware contexts. Machine-readableinstructions stored on any of the above-mentioned storage media may beexecutable by the processor 1102. For example, a computer program mayinclude machine-readable instructions capable of handling in-deviceco-existence interference between non-serving LTE frequencies and an ISMfrequency, according to the teachings and herein described embodimentsof the present subject matter. In one embodiment of the presentinvention, the computer program may be included on a storage medium andloaded from the storage medium to a hard drive in the non-volatilememory.

In accordance with the one or more embodiments described in FIGS. 3through 11, the UE 301 starts measurements on the neighboring interfrequency cells (e.g., the non-serving LTE frequencies) when the signalquality of the serving cell falls below a threshold since the basestation 310 requires some measurements from the UE 301 on theneighboring inter frequency cells in order to make a handover.Therefore, if the ISM activity is complete, the UE 301 triggers arequest for configuring the at least one of non-serving LTE frequencyfor performing measurements. In response, the UE 301 receives an updatedlist of non-serving LTE frequencies from the base station 310, whereinthe updated list of non-serving frequencies includes the at least one ofthe non-serving LTE frequencies. Accordingly, the UE 301 configures thenon-serving LTE frequencies in the updated list of non-serving LTEfrequencies for performing a measurement.

Further, when the base station 310 is configuring non-serving LTEfrequencies and the affected non-serving LTE frequencies were blockedprior to the configuration, the UE 301 may send a request to the basestation 310 for configuring the blocked non-serving LTE frequencies forperforming a measurement or be made as a serving frequency. For example,the UE 301 may communicate the request to the base station 310 eitherusing a new cause and/or an information element in the connectionreconfiguration complete message.

Furthermore, when there are no new measurement configurations, signalquality of the serving cell has fallen below a threshold value and theISM module 306 is turned off, the UE 301 can send an indication to thebase station 310 that the blocked non-serving LTE frequencies arere-configured for performing a measurement.

In an idle mode, the UEs typically perform cell reselections to keepthemselves connected to the base station 310, receive paging, read thesystem information, and the like. The decision to perform cellreselection is based on serving a cell signal strength, ranking with theneighbor and network provided cell reselection priorities. Because ofthe network provided reselection priorities, the UE 301 may be forced toreselect to an LTE frequency affected by the ISM activity, therebyleading to problems in subsequent connection and triggering FrequencyDivision Multiplexing (FDM) based solutions.

In one embodiment of the present invention, the UE 301 performsreselection procedure on an LTE frequency which is not interfered by theISM activity as the UE 301 considers the priority of interfering orinterfered LTE frequencies to be lower than any of the priorities givenby the network even if the network has signaled it to be a highpriority. This is advantageous as if more than one frequency isavailable for reselection. The above rule prioritizes the non-interferedfrequencies. Further, if only the affected LTE frequency is availablefor reselection, the cell reselection procedures make sure that this LTEfrequency is only reselected if the serving cell is having a low signalstrength.

In another embodiment of the present invention, the UE 301 is forced tore-select a frequency which is not interfered by the ISM activity as theUE 301 considers priorities of the interfering or interfered LTEfrequencies to be lower than the priority of the serving LTE frequency,provided the UE 301 is given and is valid even if the network hassignaled it to be a high priority.

When making a connection to the base station 310, the UE 301 may becamped on an LTE frequency or the LTE frequency on which the UE 301 isattempting to make the connection establishment is affected by an ISMactivity. In such a case, the UE 301 may to trigger an FDM basedsolution at the end of connection establishment. As the FDM solutionrequires a handoff to be triggered and the handoff may only happen withthe measurements and after completion of the security procedures whichinvolves a substantial delay. As a result, the connection may bedropped.

In one embodiment of the present invention, when the UE 301 is aware ofISM interference on the camped LTE frequency at the time of radioresource connection establishment, the UE 301 communicates a likelihoodof in-device co-existence interference between the camped LTE frequencyand the ISM frequency either in an RRC connection request message or anRRC connection setup complete message. Based on the indication, the basestation 310 becomes aware that the camped LTE frequency is affected bythe ISM frequency and the ISM module 306 is ON. Thus, the base station310 can move the UE 301 to an LTE frequency which is not affected by theISM frequency. The movement can be either by accelerating measurementand handover procedure or by releasing the connection by providing thenecessary parameters in the release message, such as redirection anddedicated cell reselection priorities.

While the invention has been shown and described with reference tocertain embodiments thereof, it will be understood by those skilled inthe art that various changes in form and details may be made thereinwithout departing from the spirit and scope of the invention as definedby the appended claims and their equivalents.

1. A method comprising: detecting a likelihood of in-device coexistenceinterference between at least one of non-serving Long Term Evolution(LTE) frequencies and an Industrial, Scientific and Medical (ISM)frequency when an ISM activity is ongoing on the ISM frequency; andreporting the likelihood of in-device coexistence interference betweenthe at least one of the non-serving LTE frequencies and the ISMfrequency to a base station.
 2. The method of claim 1, wherein thedetecting of the likelihood of in-device coexistence interferencebetween the at least one of the non-serving LTE frequencies and the ISMfrequency when the ISM activity is ongoing on the ISM frequencycomprises: receiving a list of the non-serving LTE frequencies so as toperform a measurement on the non-serving LTE frequencies from the basestation; configuring the non-serving LTE frequencies in the receivedlist so as to perform the measurements on the configured non-serving LTEfrequencies; detecting the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency when the ISM activity is ongoing on the ISMfrequency.
 3. The method of claim 2, wherein the reporting of thelikelihood of in-device coexistence interference between the at leastone of the non-serving LTE frequencies and the ISM frequency to the basestation comprises: reporting the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency to the base station; receiving a measurementreconfigure message from the base station in response to the reporting,wherein the measurement reconfigure message includes an indication toremove the at least one of the non-serving LTE frequencies; and removingthe at least one of the non-serving LTE frequencies from the configurednon-serving LTE frequencies.
 4. The method of claim 1, wherein thedetecting of the likelihood of in-device coexistence interferencebetween the at least one of the non-serving LTE frequencies and the ISMfrequency when the ISM activity is ongoing on the ISM frequencycomprises: receiving a first Radio Resource Connection (RRC)reconfiguration message with a list of the non-serving LTE frequenciesfrom the base station; configuring the non-serving LTE frequencies inthe received list so as to perform a measurement on the configurednon-serving LTE frequencies; and detecting the likelihood of in-devicecoexistence interference between the at least one of the non-serving LTEfrequencies and the ISM frequency when the ISM activity is ongoing onthe ISM frequency.
 5. The method of claim 4, wherein the reporting ofthe likelihood of in-device coexistence interference between the atleast one of the non-serving LTE frequencies and the ISM frequency tothe base station comprises: transmitting an RRC reconfiguration completemessage indicating the likelihood of in-device coexistence interferencebetween the at least one of the non-serving LTE frequencies and the ISMfrequency to the base station.
 6. The method of claim 5, wherein thetransmitting of the RRC reconfiguration complete message indicating thelikelihood of in-device coexistence interference between the at leastone of the non-serving LTE frequencies and the ISM frequency to the basestation further comprises: receiving a second RRC reconfigurationmessage with an updated list of non-serving LTE frequencies from thebase station in response to the RRC reconfiguration complete message;and configuring the non-serving LTE frequencies in the updated list soas to perform the measurement on the configured non-serving LTEfrequencies.
 7. The method of claim 5, wherein the transmitting of theRRC reconfiguration complete message indicating the likelihood ofin-device coexistence interference between the at least one of thenon-serving LTE frequencies and the ISM frequency to the base stationfurther comprises: removing the at least one of the non-serving LTEfrequencies and corresponding measurement gaps from the configurednon-serving LTE frequencies.
 8. The method of claim 1, wherein thedetecting of the likelihood of in-device coexistence interferencebetween the at least one of the non-serving LTE frequencies and the ISMfrequency when the ISM activity is ongoing on the ISM frequencycomprises: receiving a first Radio Resource Connection (RRC)reconfiguration message with a handover command so as to performhandover from a serving LTE frequency to the at least one of thenon-serving LTE frequencies; and detecting the likelihood of in-devicecoexistence interference between the at least one of the non-serving LTEfrequencies and the ISM frequency when the ISM activity is ongoing onthe ISM frequency, and wherein the reporting of the likelihood ofin-device coexistence interference between the at least one of thenon-serving LTE frequencies and the ISM frequency to the base stationcomprises: rejecting the handover command in the RRC reconfigurationmessage; transmitting an RRC reconfiguration complete message indicatingthe likelihood of in-device coexistence interference between the atleast one of the non-serving frequencies and the ISM frequency to thebase station; and receiving a second RRC reconfiguration message with anew handover command so as to perform handover from the serving LTEfrequency to another non-serving LTE frequency that is neitherinterfered by an ISM activity nor causing in-device coexistenceinterference to the ISM activity.
 9. The method of claim 1, wherein thelikelihood of in-device coexistence interference between the at leastone of the non-serving frequencies and the ISM frequency is notified tothe base station through a measurement report.
 10. The method of claim1, wherein the detecting of the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency when the ISM activity is ongoing on the ISMfrequency comprises: receiving a Radio Resource Connection (RRC)reconfiguration message with a handover command so as to performhandover from a serving LTE frequency to the at least one of thenon-serving LTE frequencies; and detecting the likelihood of in-devicecoexistence interference between the at least one of the non-serving LTEfrequencies and the ISM frequency when the ISM activity is ongoing onthe ISM frequency, and wherein the reporting of the likelihood ofin-device coexistence interference between the at least one of thenon-serving LTE frequencies and the ISM frequency to the base stationcomprises: rejecting the handover command in the RRC reconfigurationmessage; triggering an RRC re-establishment procedure forre-establishing a radio resource connection with the base station; andtransmitting an RRC re-establishment request message indicating thelikelihood of in-device coexistence interference between the at leastone of the non-serving frequencies and the ISM frequency to the basestation.
 11. The method of claim 1, wherein the reporting of thelikelihood of in-device coexistence interference between the at leastone of the non-serving LTE frequencies and the ISM frequency to the basestation further comprises: receiving a timer value during which the atleast one of the non-serving LTE frequencies is blocked so as to performa measurement from the base station; receiving an updated list of thenon-serving LTE frequencies from the base station upon expiry of thetimer value, wherein the updated list of non-serving frequenciesincludes the at least one of non-serving LTE frequencies; andconfiguring the non-serving LTE frequencies in the updated list ofnon-serving LTE frequencies so as to perform the performing measurement.12. The method of claim 1, wherein the reporting of the likelihood ofin-device coexistence interference between the at least one of thenon-serving LTE frequencies and the ISM frequency to the base stationcomprises: reporting the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency to the base station and a timer value during whichthe at least one of the non-serving LTE frequencies is to be blocked forso as to perform a measurement; receiving an updated list of thenon-serving LTE frequencies from the base station upon expiry of thetimer value, wherein the updated list of the non-serving frequenciesincludes the at least one of the non-serving LTE frequencies; andconfiguring the non-serving LTE frequencies in the updated list of thenon-serving LTE frequencies so as to perform the measurement.
 13. Themethod of claim 3, further comprising: setting a timer value duringwhich the at least one of the non-serving LTE frequencies is to beblocked so as to perform the measurement; and adding the removed atleast one of the non-serving LTE frequencies in the configurednon-serving LTE frequencies upon expiry of the timer value, wherein theexpiry of the timer value indicates that the ISM activity is completed.14. The method of claim 1, further comprising: indicating to the basestation that the ISM activity has completed.
 15. The method of claim 14,further comprising: determining whether a signal quality of a servingLTE frequency is below a threshold; triggering a request for configuringthe at least one of the non-serving LTE frequency so as to perform ameasurements; receiving an updated list of the non-serving LTEfrequencies from the base station, wherein the updated list of thenon-serving frequencies includes the at least one of the non-serving LTEfrequencies; and configuring the non-serving LTE frequencies in theupdated list of the non-serving LTE frequencies so as to perform themeasurement.
 16. The method of claim 3, wherein the removing of the atleast one of the non-serving LTE frequencies from the configurednon-serving LTE frequencies further comprises: sending a Radio ResourceConnection (RRC) reconfiguration complete message including a request tore-configure the at least one of the non-serving LTE frequencies to thebase station.
 17. The method of claim 3, wherein the removing of the atleast one of the non-serving LTE frequencies from the configurednon-serving LTE of frequencies further comprises: sending an indicationto the base station that the removed at least one of the non-serving LTEfrequencies are re-configured by a user equipment when the ISM activityis complete and the signal quality of a serving frequency has fallenbelow a threshold value.
 18. The method of claim 1, further comprising:performing a re-selection procedure on one of the non-serving LTEfrequencies that is not affected by the ISM activity, wherein the one ofthe non-serving LTE frequencies is having a lower priority than the atleast one of the non-serving LTE frequencies which is affected by theISM activity.
 19. The method of claim 1, further comprising: performinga re-selection procedure on a previously serving LTE frequency that isnot affected by the ISM activity, wherein the previously serving LTEfrequency is having a lower priority than the at least one of thenon-serving LTE frequencies which is affected by the ISM activity. 20.The method of claim 1, wherein the reporting of the likelihood ofin-device coexistence interference between the at least one of thenon-serving LTE frequencies and the ISM frequency to the base stationcomprises: reporting the likelihood of in-device coexistenceinterference between the at least one of the non-serving LTE frequenciesand the ISM frequency to the base station during establishment of aradio resource connection so that a user equipment is moved to anon-serving LTE frequency which is not affected by the ISM activity,wherein the non-serving LTE frequency which is not affected by the ISMactivity is an LTE frequency on which the user equipment is camped forestablishing the radio resource connection.
 21. An apparatus comprising:a processor; and a memory coupled to the processor, wherein the memoryincludes an interference handler configured to detect a likelihood ofin-device coexistence interference between at least one of non-servingLong Term Evolution (LTE) frequencies and an Industrial, Scientific andMedical (ISM) frequency when an ISM activity is ongoing on the ISMfrequency, and configured to report the likelihood of in-devicecoexistence interference between the at least one of non-serving LTEfrequencies and the ISM frequency to a base station.
 22. The apparatusof claim 21, wherein the interference handler is further configured toreceiving to receive a list of the non-serving LTE frequencies so as toperform a measurements on the non-serving LTE frequencies from the basestation, and to configure the non-serving LTE frequencies in thereceived list so as to perform the measurement on the configurednon-serving LTE frequencies.
 23. The apparatus of claim 22, wherein theinterference handler is further configured to receive a measurementreconfigure message from the base station in response to reporting thelikelihood of in-device coexistence interference, wherein themeasurement reconfigure message includes an indication to remove the atleast one of the non-serving LTE frequencies, and to remove the at leastone of the non-serving LTE frequencies from the configured non-servingLTE frequencies.
 24. The apparatus of claim 23, wherein the interferencehandler is further configured to indicate to the base station that theISM activity has completed.